Perform studies for the development of immunological assays for the diagnosis of human cancer. Tumor and normal tissue specimens shall be obtained from carcinomas of the colon, stomach, lung, breast, prostate, and bladder. Fetal tissue shall be obtained from legal abortions. Antigens shall be extracted and heterologous antisera prepared against each of the antigens. Antigens shall be purified and procedures shall be performed to render the antisera specific for tumor associated antigens. Radioimmunoassay shall be developed for the detection of each antigen in serum or urine. Sera from patients with cancer and with benign diseases and from normal individuals shall be tested for the presence of circulating antigen.